The Prusa MK3 Clone: The Hot End Part 3

When you have followed my previous post, you know that the CNC machined aluminum mount for the Titan Extruder did not work for my Titan Aqua Klon as the Titan Aqua is quite different from the Titan Extruder or Titan Aero Hot End.

By accident I stumbled across a mount on thingiverse from Chris Vahi from Vancouver . He did an awesome job in designing and testing a mount for the Titan Aqua that can be screwed on to the original Prusa MK3 x-carriage. So a big THANK YOU from my side to this guy.

But he did not only design the Parts you need, he also described which parameters you have to change in the Prusa Firmware to get this to work. Including the right offset for the position of the nozzle. Make sure you grab his latest design, where the P.I.N.D.A. Probe is at the same position as with the original hot end.

So I began to print all parts, including a new lever that can hold the filament sensor. Everything is printed with PETG from Prusa(not Prusament) in black. I was able to print everything without support, I just needed to adjust the orientaion when I imported the STL files in Slic3r PE.
There is the mount, the angled mount for the print cooling fan(just like in the new Prusa versions), the new lever with top cover for the filament sensor.

On the left is the original lever that came with my Titan Aqua Klon and the on the right side the the 3D printed version from Chris design. The big top is the housing for the filament sensor.

As the original lever use a ball bearing to press the filament to the drive gear. In Chis design he make use of the bond tech gear from the original MK3 hot end. I had a set of bond tech klon gears ordered from aliexpress that I use here.

Basically like in the Prusa design the gear is held in place by the shaft that is pushed thru the holes in the 3D printed part.

You just need this part from the set, not the one that usually goes on to the stepper motor shaft. Chis explains in his instructions in Thingiverse why you cannot easily use the other gear, as you would have to modify the shaft of the original gears that come with the Titan Aqua.

So I don't see what sense it makes to use the bond tech gear on the other side if it is not driven by the other gear. I don't see why this is better then the ball bearing. But that is my opinion, not even having tested it yet. Maybe the silhouette of the bond tech helps to align the filament better than the flat bearing surface.

Before you start I strongly recommend watching the assembly instruction video from Triangel Lab(my Klon was from D Force) and the original E3D instructions. I will give you some additional tips below as the video from Triangle Labs does only have music and they don't mention some important things.

Now it was time to prepare the rest of the parts. Mine came partially pre assembled, but I need to take it apart to install it the proper way. The shaft of the gear is secured with a spring washer. Don't take this apart, it is not necessary.

I started to screw in the pneumatic connectors to the thin aluminum plate. Use only moderate force to tighten them, when you ruin the threads, your hot end will leak. Make sure you remove the protection foil from both side of the gasket. Mine was hard to spot as they are all transparent.

First put the drive gear on the stepper motor shaft and make sure the side with the set screw is closer to the motor. Otherwise the set screw will block the gear afterwards.

Then put the part together without any thermal compound to test if you can move the gears and the set screw is not blocking and to see that the gears are flush.

Now we need the thermal compound that came with the kit. There is enough of this for the assembly if you don't waste anything.

The next step is to apply a bit of the thermal compound to the surface. Don't use too much, this is only to cool down the extruder motor as well. You need more of this stuff on more important parts.

Also check the surface of you stepper motor, my cheap blurolls motors have some gap in the surface that will not touch the aluminum parts, so they don't need the thermal compound either.

Then put it together and secure the aluminum part with the short screw to the motor.

In the next step we need to make sure we use enough thermal compound, because this is the surface between the part with the water cooling and the part where the heat brake gets screwed in. It is essential to have a good thermal conduction here. But leave something for the heat break later.

And make sure you have the assembled new lever ready now to attach it to the stepper motor shaft.

Now we need to put the two parts together and secure them with the mid length screw on the right side to the other aluminum part and with the 2 long screws on the left side to the stepper motor.
Then you screw in the adjustment screw with the spring. Not a bad idea too test again that the gears are still working fine.

I also checked the alignment of the bond tech klon gear with the drive gear.

For the next step you need to prepare a piece of the PTFE tube that is 7mm long. I used a digital caliper and a sharp knife for masking tape.

I will not use the heat brake that came with the Titan Aqua klon, they are full metal ones and seem to be ok. But I bought some Titanium alloy heat breaks from aliexpress some time ago. How I know it is no fake? Well, I tested them with a magnet to make sure it is not steel, then I measured the weight with a precise scale and they are lighter than the steel ones I have. So there is a good chance it is some Titanium alloy. All the other methods I found are destructive, so I did not do it.

My heat block came pre assembled with heater cartridge, NTC sensor and nozzle. It disassembled them as I wanted to have my cables on the other side and it made the assembly of the heat break and the heat block easier.
IMPORTANT! Not you need to apply some of the thermal compound as well on the heat break. BUT ONLY on the upper part, the longer threads. Stay away with the thermal compound from the lower part!
You want to increase the thermal conductivity from the heat break to the heat sink, to help to cool it down. You don't want to help transfer more heat from the heat block into the heat break!

Screw in the heat break into the Titan Aqua alu part. Then it is a good time to use a paper towel to wipe of all the excess thermal compound of the part and wash your hands. This stuff is not very healthy!

Screw on the heat block and counter it with the nozzle. Once than is done you can insert the NTC and the heater cartridge again.

Mine looks like this, as I wanted to have the heater block orientation exactly the same as on my original MK3 hot end.

Now it was time to attach the mount that Chris designed and I found out that it did not fit. As you can see the arm of the mount is to thick as pushes on the pneumatic connectors. This is not good, either the threads get damaged or the thin aluminium plate get bended. In both cases the hot end will leak.

So back to the drawing board, or better Fusion 360. I imported the files from Chris and started to modify them. First I cut out a space for the pneumatic connectors.

Then I beefed up the other side a bit to compensate for the loss of rigidity with the cut out.

Finally I just added some fillets to make it more appealing.

I have uploaded my remixed files to Thingiverse if someone else needs them.

Here you can see the difference between my remixed version and the original version from Chris Vahi.

The part fits perfectly now, so it was time to press in the 3 M3 nuts and 1 M3 square nut.

To mount the Titan Aqua to the mount you need 3 M4x12mm screws and 1 M4x16 for the fan mount. Of course I have don't have the right size here, as you can see. So I have to order them and replace them later.
To attach the mount then to the Prusa x-carriage you need 1 M3x10mm and 2 M3x16mm screws.